Sounds small, but it's hit as much as a 2% spread [0]. More importantly, they take this off of every transaciton. It makes FDI much cheaper for them when they go into other countries. It allows them to debase their currency internally and reap the benefits while charging others with a stronger external currency. When you factor in shadow banking etc., the exchange rate is not the same as the actual value inside China, because she is such a heavily gated market. These capital controls are precisely what pisses the rest of the world off: the whole point of the WTO and trade treaties is that you don't get to pull this garbage. When you factor in the multipliers etc. across the world, China has skimmed huge sums of cash off the top of the global market. [1]

[0] https://currenxie.com/blog/how-to-take-advantage-of-the-cny-...

[1] https://twitter.com/adamscrabble/status/1094717028009689089